RESOLVED FIXED83665
[TexmapGL] Reduce the number of glTexSubImage2D calls 
https://bugs.webkit.org/show_bug.cgi?id=83665
Summary [TexmapGL] Reduce the number of glTexSubImage2D calls
Igor Trindade Oliveira
Reported 2012-04-10 23:18:05 PDT
When the OpenGLES driver does not support GL_EXT_unpack_subimage, BitmapTextureGL::updateContents is transfering the pixels row by row, sometimes calling glTexSubImage2D more than 40 times. This approach is ok for almost all drivers, however for some low end drivers can be a problem.
Attachments
Patch (2.80 KB, patch)
2012-04-10 23:24 PDT, Igor Trindade Oliveira 		no flags
DetailsFormatted DiffDiff
Patch (2.78 KB, patch)
2012-04-11 10:41 PDT, Igor Trindade Oliveira 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Igor Trindade Oliveira
Comment 1 2012-04-10 23:24:24 PDT
Created attachment 136630 [details] Patch Proposed patch.
Noam Rosenthal
Comment 2 2012-04-11 05:07:06 PDT
Comment on attachment 136630 [details] Patch Any idea if this is actually faster?
Igor Trindade Oliveira
Comment 3 2012-04-11 10:41:13 PDT
Created attachment 136695 [details] Patch Proposed patch v2.
Igor Trindade Oliveira
Comment 4 2012-04-11 10:47:07 PDT
i did some tests using callgrind and it shows improvements. But it also depends of the graphics driver, in mali drivers i believe the memory is shared between the cpu and gpu so the old code can be fast. (In reply to comment #2) > (From update of attachment 136630 [details]) > Any idea if this is actually faster?
Noam Rosenthal
Comment 5 2012-04-11 11:02:37 PDT
Comment on attachment 136695 [details] Patch This still feels a bit like a micro-optimization that might have different results on different graphics drivers... I'd rather come back to this after we know the pros/cons better.
Dongseong Hwang
Comment 6 2012-06-15 22:24:47 PDT
I think less glTexSubImage2D call is better, although I have no clue to convince you. http://origin-developer.nvidia.com/docs/IO/8230/BatchBatchBatch.pdf?q=docs/IO/8230/BatchBatchBatch.pdf It is be widely known that less drawing call, better performance. So, I think the fact may apply glTexSubImage2D, also, because glTexSubImage2D causes data transfer from cpu to gpu like drawing call.
Noam Rosenthal
Comment 7 2012-06-16 06:57:55 PDT
Comment on attachment 136695 [details] Patch OK, I think you have some merit.
WebKit Review Bot
Comment 8 2012-06-16 09:16:36 PDT
Comment on attachment 136695 [details] Patch Clearing flags on attachment: 136695 Committed r120527: <http://trac.webkit.org/changeset/120527>
WebKit Review Bot
Comment 9 2012-06-16 09:16:40 PDT
All reviewed patches have been landed. Closing bug.
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